Suchergebnisse

Regional studies on the erosive power of rainfall patterns are still limited and the actual impacts that may follow on erosional and sedimentation processes are poorly understood. Given the several interrelated challenges of environmental management, it is also not always unclear what is relevant for the development of adaptive and integrated approaches facilitating sustainable water resource management. This editorial introduces the Special Issue entitled &ldquo ; Rainfall Erosivity in Soil Erosion Processes&rdquo ; which offers options to fill some of these gaps. Three studies performed in China and Central Asia (by Duulatov et al., Water 2019, 11, 897, Xu et al., 2019, 11, 2429, Gu et al. 2020, 12, 200) show that the erosion potential of rainfall is increasing in this region, driving social, economic, and environmental consequences. In the same region (the Weibei Plateau in China), Fu et al. (Water 2019, 11, 1514) assessed the effect of raindrop energy on the splash distance and particle size distribution of aggregate splash erosion. In the Mediterranean, updated estimates of current and future rainfall erosivity for Greece are provided by Vantas et al. (Water 2020, 12, 687), while Diodato and Bellocchi (Water 2019, 11, 2306) reconstructed and investigated seasonal net erosion in an Italian catchment using parsimonious modelling. Then, this Special Issue includes two technologically oriented articles by Ricks at al. The first (Water 2019, 11, 2386) evaluated a large-scale rainfall simulator design to simulate rainfall with characteristics similar to natural rainfall. The data provided contribute to the information that may be useful for the government's decision making when considering landscape changes caused by variations in the intensity of a rainfall event. The second article (Water 2020, 12, 515) illustrated a laboratory-scale test of mulching methods to protect against the discharge of sediment-laden stormwater from active construction sites (e.g., highway construction projects).

29 Pags.- 6 Tabls.- 6 Figs. This article belongs to a special issue of Catena titled "Geoecology in Mediterranean mountain areas. Tribute to Professor José María García Ruiz". The definitive version is available at: http://www.sciencedirect.com/science/journal/03418162 ; Understanding how organic carbon (OC) moves with sediments along the fluvial system is crucial to determining catchment scale carbon budgets and helps the proper management of fragile ecosystems. Especially challenging is the analysis of OC dynamics during fluvial transport in heterogeneous, fragile, and disturbed environments with ephemeral and intense hydrological pulses, typical of Mediterranean conditions. This paper explores the catchment scale OC redistribution by lateral flows in extreme Mediterranean environmental conditions, from a geomorphological perspective. The study area is a catchment (Cárcavo) in SE Spain with a semiarid climate, erodible lithologies, and shallow soils, which is highly disturbed by agricultural terraces, land levelling, reforestation, and construction of check-dams. To increase our understanding of catchment scale OC redistribution induced by erosion, we studied in detail the subcatchments of eight check-dams distributed along the catchments main channel. We determined 137Cs, physicochemical characteristics, and the OC pools of the catchment soils and sediments deposited behind each check-dam, performed spatial analysis of catchment properties and buffer areas around the check-dams, and carried out geomorphological analysis of the slope-channel connections. The soils showed very low total organic carbon (TOC) values, oscillating between 15.2 and 4.4 g kg− 1 for forest and agricultural soils, respectively. Sediments mobilized by erosion were poor in TOC (6.6 ± 0.7 g kg– 1) compared to the eroded (forest) soils, and the redistribution of OC through the catchment, especially of the mineral associated organic carbon (MAC) pool, showed the same pattern as clay particles and 137Cs. The TOC erosion rates estimated for the Cárcavo watershed are relatively low (0.031 ± 0.03 Mg ha− 1 y− 1) but similar to those reported for subhumid Mediterranean catchments that are less fragile and more conducive to plant growth. The TOC erosion/total erosion ratio was lower (0.06%) than other estimates, although the average OC concentration of the sediments was higher than that of the agricultural soils of the catchment, underlining the problem of maintaining sustainable soil OC contents. The OC in deposited sediments came not only from surface erosion processes, but also from deeper soil or sediment layers mobilized by concentrated erosion processes. Sediment richer in OC came from the surface soil of vegetated (reforested) areas close and well connected to the channels. Subcatchments dominated by laminar erosion processes showed a TOC erosion/total erosion ratio that was two times higher than that of subcatchments dominated by concentrated flow erosion processes. The lithology, soils, and geomorphology exert a more important control on OC redistribution than land use and vegetation cover in this geomorphologically very active catchment. ; This work was financially supported by the projects ADAPT (CGL2013-42009-R) and DISECO (CGL2014-55-405-R) from the Spanish Government, National Plan of Science; the project CAMBIO (18933/JLI/13) of the Seneca Foundation, Regional Government of Murcia (Spain); and the project SOGLO (P7/24 IAP BELSPO) from the Belgian Government. Joris de Vente was supported by a 'Ramón y Cajal' grant (RYC-2012-10375). ; Peer reviewed

The Southern Bărăgan Plain is a geographical unit where the rainfall processes have a moderate action, even reduced in some places, taking into account the low rainfall as well as the morphology and morphometers of the relief. These processes have an impact on man and human activities, primarily through the action they have on land on which intensive agriculture is practiced or even on inhabited areas.

Abstract. A landslide dam typically comprises freshly deposited heterogeneous, unconsolidated or poorly consolidated earth materials and is vulnerable to overtopping breaching. A physically-based breach model is presented to simulate the breaching process of such landslide dams. The new model can predict the breach evolution, the erosion rate, and the outflow hydrograph. A spreadsheet is developed to numerically implement the model. The erosion processes of Tangjiashan Landslide Dam and Xiaogangjian Landslide Dam induced by the 2008 Wenchuan earthquake are analyzed using the new model. The erodibility of the two landslide dams varies significantly along depth. The predicted key breaching parameters (i.e., final breach size, failure time, and peak outflow rate) considering the variations in the soil erodibility along depth agree well with the observed values. Further sensitivity analysis indicates that the soil erodibility affects the breaching process of a landslide dam significantly. Higher soil erodibility will lead to a larger breach, a shorter failure time and a larger peak outflow rate. The erosion rate of the breach channel in the depth direction decreases with increasing erosion resistance of the landslide deposits. In the two case studies, the key breaching parameters cannot be properly predicted if constant soil erodibility parameters along depth are assumed.

AbstractThis paper explores the effects of debt erosion on the market process. Debt erosion is the attempt by government to lower the real value of its debt through the creation of unexpected inflation. In addition to the costs recognised by most economists, debt erosion through unexpected inflation can impair the price system's ability to coordinate exchange activity and can result in costly capital misallocations. This is because the creation of unexpected inflation implies disequilibrium in the money market. To avoid the harm from such monetary shocks, this paper suggests a separation between money and state, enshrined in an explicit rule at the constitutional level.